Drill bits



J1me 1962 J. T. WILLIAMS 3,040,825

DRILL BITS J. T.WILLIAMS 5 anja A TTORNE Y United States Patent Ofiice3,940,825 Patented June 26, 1962 3,048,825 DRILL BITS James T. Williams,313 S. 3rd St., Tonkawa, Okla. Filed June 4, 1959, Ser. No. 818,029 2Claims. (Cl. 175412) This invention relates to drill bits and moreparticularly to detachable blade drill bits. Drill bits of this typewhether or not the blades are detachable are generally referred to inthe art as drag bits. With drag bit construction the blade portions wearrapidly by abrasion against the earth formations and it is desirable toreplace the blades while retaining or salvaging the body and otherportions of the bit. Great difiiculty is encountered, however, insecurely afiixing the blades to the bit body so as to avoid loosening ofthe blades due to the chattering of the bit.

It is not uncommon to conduct the drilling operation in the rotarymethod of drilling wells by applying weights approximately ten, twentyor even thirty thousand pounds to the drill bit by lowering the weightof the drill stem or operating pipe onto the bit. When it is consideredthat the bit may be rotated at fifty to one hundred revolutions perminute while having a tremendous weight of this sort applied to it, itseems obvious that the bit is chattering against the formation. Thischatter action tends to loosen all previous types of detachable bladebits with which I am familiar, and the present invention thereforecontemplates a particular arrangement of the structure whereby theblades are securely wedged in position and retained against looseningwhile under use under the most exacting conditions. Furthermore, anylooseness between the blade and the body causes a large increase in therate of wear of both the blade and the drill body. In addition loosenessincreases the tendency of the blades to break off in the well. Anybreakage is objectionable because the broken part must not only bereplaced but the broken part must be fished out of the hole beforedrilling operations can be continued. This, of course, is expensive andtime consuming.

Since the inception of drilling, diificulty has been encountered in thewearing away of the cutting blades. With the advent of deeper drilling,considerable time is expended in removing the string of drill pipes, sayfrom a or 15,000 foot hole by uncoupling the hundreds of sections ofdrill pipe which have been added so as to elevate the bit to thesurface. The worn bit is then removed and a fresh bit attached whereuponthe drill pipe is then lowered to carry the bit to the bottom of thewell bores.

It had been found that in a majority of instances, there is practicallyno wear to the body of the drilling bit which is connected to the drillpipe and that practically the only wear occurs on the cutting edges orlower portions of the drilling bit. It is therefore a principal objectof the present invention to provide a detachable blade bit that obviatesthe difficulties of the prior art bits.

It is another object of my invention to provide a bit having detachableblades which can be readily mounted and dismounted upon the drill body.

Another object of this invention is to provide a bit having detachableblades which can be easily replaced when worn with new blades. Otherobjects and advantages of the invention will become apparent when thefollowing description is considered in connection with the accompanyingdrawings wherein:

FIG. 1 is an elevation of a bit constructed in accordance with myinvention.

FIG. 2 is a cross-sectional view taken on the line 22 of FIG. 1.

FIG. 3 is an elevation of one of the detachable bits showing thevertical and horizontal ribs.

FIG. 4 is an elevation partly .in section of the drill bit.

In FIG. 1 the drill bit is caused to be rotated and the drilling mud iscirculated through the passage 9 shown in FIGS. 2 and 4 thereof todischarge from the bit in order to accomplish the various functions ofsaid drilling mud, such as carrying away of the cuttings, the cooling ofthe bit, the creating of a filter cake on the face of the well bore, andfor maintaining the bore against caving, all of which are known in theart.

The bit body 3 also shown in FIGS. 2 and 4 is so constructed that it hasa downwardly and outwardly tapered conical surface adjacent its lowerend which is provided with longitudinal circumferentially spaced grooves1 and horizontal groove 2 so as to form a blade segment supportingsurface.

Each of the blade segments 4 has an outer arcuate surface 10 which isarranged to receive the inner conical surface of a clamping or drivingcollar 5. This collar slides over the shank surfaces 10 and upper edge10a of drill bits segments 4 and is forced into position by a drivingsub 12, FIG. 1, internally threaded to fit the threads 11.

The ribs 6 and 8 of the detachable blade 4 mate with the grooves 1 and 2of the drill body. It should be noted that the rib 6 extends verticallyon the inner shank portion of the detachable drill blade and is locatedat a point remote from the edges thereof. With this construction, theblade segments 4 are firmly clamped in position and are thus securelyheld.

Although I have illustrated my invention utilizing a drill bit havingthree detachable blades attached thereto, it will be readily apparent tothose skilled in the art that the invention is equally applicable to abit having four detachable bits. Also as is apparent the abrading andfracturing drill bits may be replaced with rock drilling bits and othertypes of drilling bits.

Broadly stated, the invention contemplates a detachable blade bitwherein the blades are secured upon the bit body by the wedging actionof a clamping collar. In addition to the wedging action of the collarthe drill bit body is provided with a plurality of circumferentiallyspaced longitudinal or vertical grooves and a circumferential grooveintersecting the vertical grooves. The detachable bits are provided witha shank curved transversely to mate with a portion of the outerperiphery of the tapered portion of the drill bit body. Verticalextending ribs on the shank portions of the detachable bits and spacedon the shank at a point adjacent one of the edges thereof are so shapedthat they mate with the vertical grooves in the drill body. In thismanner the direct thrust of the rotative force of the drill stem anddrill collar against the clamping collar is transmitted to the bladesand bit body by the clamping collar so that rigid securing means isprovided.

While particular embodiments of the invention have been described, itwill be understood, of course, that the invention is not limited theretosince many modifications may be made, and it is therefore contemplatedto cover by the appended claims any such modifications as fall withinthe true spirit and scope of the invention.

The invention having thus been described, what is claimed and desired tobe secured by Letters Patent is:

l. A detachable blade rotary drilling bit comprising a tubular bodyhaving an upper end and a lower end and reduced in its outer diameter inupwardly spaced relation from its lower end to provide a downwardly andoutwardly tapered conical surface, a plurality of circumferentiallyspaced longitudinal grooves in said conical surface and acircumferential groove in the outer periph- 3 ery thereof intersectingsaid vertical grooves, said vertical grooves having straight sides andbeing progressively deeper towards the lower ends thereof, a pluralityof blades having upper shank portions and lower cutting portions, theshank portion of each blade being curved transversely to mate with aportion of the outer periphery of the tapered conical surface of thebody and having a vertically extending rib therein located at a pointremote from the edges of said shank portion shaped to mate with one ofsaid vertical grooves to prevent turning of the blade in respect to thebody, there being a blade shank over each of the vertical grooves in thebody and said shanks being of a width such that the combined shanksencompass the tapered portion of the body, each shank being taperedtoward its upper end, each shank also having a horizontal rib thereon ofa size to mate with portion of the circumferential grooves in thetapered conical surface of the body, said horizontal nib being locatedon each shank to position the upper end of the shank in downwardlyspaced relation from the downwardly tapered surface on the tubular body,said shank also having an inwardly extending shoulder spaced below saidhorizontal rib a distance to extend under the lower end of the body,sleeve means having a tapered inside extending downwardly and outwardlyover the outside of said shank portions of said blades for restrainingsaid blades to said tubular body and preventing movement of said bladesin respectto said tubular body, and means connected to said tubularmember for longitudinally thrusting said sleeve to the restrainingposition.

2. A detachable blade rotary drilling bit, comprising a tubular bodyhaving its outer diameter increased toward the lower end thereof forminga downwardly and outwardly tapered mandrel on the lower end portion ofthe body, a plurality of cutting blades secured around the mandrel, eachof said blades having an upper shank portion and a lower cuttingportion, each of said shanks curved transversely to mate with the outerperiphery of the mandrel and said shanks being of a width such that thecombined shanks encompass the mandrel, said shanks also being taperedupwardly and inwardly, each blade shank also having a vertical rib onthe inner periphery thereof remote from either edge of said shank, saidmandrel having a cooperating vertical groove in the outer peripherythereof, said ribs and said grooves having straight sides to preventslippage between the blades and the body, sleeve means having a taperedinside extending downwardly and outwardly over the outside of said shankportions of said blades for restraining said blades to said tubular bodyand preventing movement of said blades in respect to said tubular body,and means connected to said tubular body for longitudinally thrustingsaid sleeve to the restraining position.

References Cited in the file of this patent UNITED STATES PATENTS

